Drop and add same key is considered rename (look ALTER_RENAME_INDEX in
fill_alter_inplace_info()). But in this case order of keys may be
changed, because mysql_prepare_alter_table() yet does not know about
rename and treats 2 operations: drop and add.

In that case we disable inplace algorithm for such engines as Memory,
MyISAM and Aria with ALTER_INDEX_ORDER flag. These engines have no
specialized check_if_supported_inplace_alter() and default
handler::check_if_supported_inplace_alter() sees an unknown flag and
returns HA_ALTER_INPLACE_NOT_SUPPORTED.

ha_innobase::check_if_supported_inplace_alter() works differently and
inplace is not disabled (with the help of modified
INNOBASE_INPLACE_IGNORE). add_drop_v_cols fork was also tweaked as it
wrongly failed with MSG_UNSUPPORTED_ALTER_ONLINE_ON_VIRTUAL_COLUMN
when it seen ALTER_INDEX_ORDER.

No-op operation must be still no-op no matter of ALTER_INDEX_ORDER
presence, so we tweek its condition as well.

mysql_prepare_create_table() does my_qsort(sort_keys) on key
info. This sorting is indeterministic: a table is created with one
order and inplace alter may overwrite frm with another order. Since
inplace alter does nothing about key info for MyISAM/Aria storage
engines this results in discrepancy between frm and storage engine key
definitions.

The fix avoids the sorting of keys when no new keys added by ALTER
(and this is ok for MyISAM/Aria since it cannot add new keys inplace).

There is a case when implicit primary key may be changed when removing
NOT NULL from the part of unique key. In that case we update
modified_primary_key which is then used to not skip key sorting.

According to is_candidate_key() there is no other cases when primary
key may be changed implicitly.

Notes:

mi_keydef_write()/mi_keyseg_write() are used only in mi_create(). They
should be used in ha_inplace_alter_table() as well.

Aria corruption detection is unimplemented: maria_check_definition()
is never used!

MySQL 8.0 has this bug as well as of 8.0.26.

The InnoDB changes in MySQL 5.7.36 that were applicable to MariaDB
were covered by MDEV-26864, MDEV-26865, MDEV-26866.

The initial test case for MySQL Bug #33053297 is based on
mysql/mysql-server@27130e25078864b010d81266f9613d389d4a229b.

innobase_get_field_from_update_vector is not a suitable function to fetch
updated row info, as well as parent table's update vector is not always
suitable. For instance, in case of DELETE it contains undefined data.

castade->update vector seems to be good enough to fetch all base columns
update data, and besides faster, and less error-prone.

In the replication-related code, in the exec_relay_log_event() (slave.cc)
function, where the "data_lock" mutex is captured, this mutex is then not
released on one of the early return branches within a specific insert for
WSREP, namely under the branch: "if (wsrep_before_statement(thd))". As a
result, the mutex remains captured, resulting in errors or hangs.

This commit fixes this issue, which is now showing up as intermittent
failures in mtr tests for galera and galera_sr suites.

ha_rocksdb.h:459:15: warning: 'table_type' overrides a member
function but is not marked 'override' [-Winconsistent-missing-override]

The assert inside String::copy() prevents copying from from "str"
if its own String::Ptr also points to the same memory.

The idea of the assert is that copy() performs memory reallocation,
and this reallocation can free (and thus invalidate) the memory pointed by Ptr,
which can lead to further copying from a freed memory.

The assert was incomplete: copy() can free the memory pointed by its Ptr
only if String::alloced is true!

If the String is not alloced, it is still safe to copy even from
the location pointed by Ptr.

This scenario demonstrates a safe copy():
  const char *tmp= "123";
  String str1(tmp, 3);
  String str2(tmp, 3);
  // This statement is safe:
  str2.copy(str1->ptr(), str1->length(), str1->charset(), cs_to, &errors);

Inside the copy() the parameter "str" is equal to String::Ptr in this example.
But it's still ok to reallocate the memory for str2, because str2
was a constant before the copy() call. Thus reallocation does not
make the memory pointed by str1->ptr() invalid.

Adjusting the assert condition to allow copying for constant strings.

Adding 10.4 specific tests.

Also fixes:
MDEV-25399 Assertion `name.length == strlen(name.str)' failed in Item_func_sp::make_send_field

Also fixes a problem that in this scenario:

SET NAMES binary;
SELECT 'some not well-formed utf8 string';

the auto-generated column name copied the binary string value directly
to the Item name, without checking utf8 well-formedness.

After this change auto-generated column names work as follows:
- Zero bytes 0x00 are copied to the name using HEX notation
- In case of "SET NAMES binary", all bytes sequences that do not make
  well-formed utf8 characters are copied to the name using HEX notation.

ALTER TABLE IMPORT doesn't properly handle instant alter metadata.
This patch makes IMPORT read, parse and apply instant alter metadata at the
very beginning of operation. So, cases when source table has some metadata
and destination table doesn't have it now works fine.

DISCARD already removes instant metadata so importing normal table into
instant table worked fine before this patch.

decrypt_decompress(): decrypts and decompresses page if needed

handle_instant_metadata(): this should be the first thing to read source
table. Basically, it applies instant metadata to a destination
dict_table_t object. This is the first thing to read FSP flags so
all possible checks of it were moved to this function.

PageConverter::update_index_page(): it doesn't now read instant metadata.
This logic were moved into handle_instant_metadata()

row_import::match_flags(): this is a first part row_import::match_schema().
As a separate function it's used by handle_instant_metadata().

fil_space_t::is_full_crc32_compressed(): added convenient function

ha_innobase::discard_or_import_tablespace(): do not reload table definition
to read instant metadata because handle_instant_metadata() does it better.
The reverted code was originally added in
4e7ee166

ANONYMOUS_VAR: this is a handy thing to use along with make_scope_exit()

full_crc32_import.test shows different results, because no
dict_table_close() and dict_table_open_on_id() happens.
Thus, SHOW CREATE TABLE shows a little bit older table definition.

Also fixes MDEV-24619 Wrong result or Assertion `0' in Item::val_native / Type_handler_inet6::Item_val_native_with_conversion

Type_handler_inet6::create_item_copy() created a generic Item_copy_string,
which does not implement val_native() - it has a dummy implementation
with DBUG_ASSERT(0), which made the server crash.

Fix:

- Adding a new class Type_handler_inet6
  which implements val_native().
- Fixing Type_handler_inet6::create_item_copy()
  to make Item_copy_inet6 instead of Item_copy_string.

Take into account client capabilities.

Sometimes, although not often, it would timeout after 3 minutes.

Happens with Innodb engine.

Move unlock_locked_table() past drop_open_table(), and
rollback current statement, so that we can actually unlock the table.

Anything else results in assertions, in drop, or unlock, or in close_table.

MDEV-25702(commit 696de6d0) should've
closed the fts table further. This patch closes the table after
finishing the bulk insert operation.

DBUG_ASSERT removed as the AUTO INCREMENT can actually be 0 when the
SET insert_id= 0; was done.

Get rid of the global big_buffer.

SysTablespace::file_not_found(): If the system tablespace cannot be
found and innodb_force_recovery has been specified, refuse to start up.
The system tablespace is necessary for accessing any InnoDB tables,
because it contains the TRX_SYS page (the state of transactions)
and the InnoDB data dictionary.

This is similar to our handling of innodb_read_only except that
we will happily create the InnoDB temporary tablespace even if
innodb_force_recovry is set.

`mytop` and `my_print_defaults` for RPM

- Add `mytop` to client package
- Add man page of `my_print_defaults` to client package
- Add dependencies for RPMs
- Remove old comment
- Remove dead link

Reviewed by: serg@mariadb.com

Make `my_print_defaults` a client app (required by `mytop`).

Closes #1566

Reviewed by: serg@mariadb.com, anel@mariadb.org

MDEV-19129: Xcode compatibility update: mysql-test-run.pl: rename $opt_vs_config to $multiconfig to use with other cmake multiconfig generators

page_create_low(): Fix -Warray-bounds

log_buffer_extend(): Fix -Wstringop-overflow